PCI driver

I have a PCI card that have to send 7 long data every400 usecs to the PC through the PCI bus.It happens that the card send a long data and wait thatthe PC reads it.Then send another data and wait and onand on.The time between the sent datas should be the same andsometimes it is not (it is longer), because I think that Windows NT does another things with higher priority and then gets the data I sent through the PCI bus.When I send a long data to the PCI, I see that it takesthe Pc 25 usec to read the data. I think that this timeis too long for the PCI bus.I do not know how to short it.When the Windows lasts more than 400us to read the datas,then the card sends the new datas, but the PChas not read the old ones, and these ones are lost.Please, I would like to know how to solve these problem.